An operating shaft (1) for operation of switching contacts in a multipole electrical power breaker has a shaft tube (2), which is intended to provide a rotating bearing, and levers (4) which project from it and are composed of dye-cast metal. These levers (4) are mounted on the shaft tube (2), which is formed from a tubular semi-finished product composed of a metal which has a higher melting point than that of the levers (4). All the levers on an operating shaft (1) can be formed as an integral dye-cast body (3) or as individual dye-cast bodies. The described configuration allows operating shafts (1) for power breakers of different sizes to be manufactured integrally.
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1. An operating shaft for operation of switching contacts in a multipole electrical power circuit breaker, having levers which project from a central shaft tube and which are composed of die-cast metal for connecting the operating shaft to the switching contacts and to an energy store which operates the switching contacts, comprising:
a shaft tube, formed by a section of a tubular semi-finished product including a metal which has a higher melting point than that of the levers which project from the shaft tube, wherein the levers are mounted on the shaft tube.
6. A method for producing an operating shaft, comprising:
provisioning a shaft tube of a tubular semi-finished product; provisioning a split casting mold for at least one lever and concentric projections to extend in an axial direction of the semi-finished product on both sides of the at least one lever; positioning the shaft tube in the split casting mold with a sealed closure on the circumference of the shaft tube; introducing a molten liquid dye-casting material into the split casting mold in order to form the at least one lever and the adjacent projections, which are concentric with respect to the shaft tube; and opening the casting mold once the die-casting material has cooled down to a reasonable extent, and removing the shaft tube with die-cast bodies, which are attached thereto and have at least one lever and adjacent sections in the form of casings.
2. The operating shaft as claimed in
all the levers are formed by an integral dye-cast body, with sections of the die-cast body which enclose the shaft tube in the form of a casing being arranged between the levers.
3. The operating shaft as claimed in
the tubular semi-finished product for the shaft tube includes steel and is at least externally electrochemically galvanized in conjunction with die-cast zinc being used as the material for the levers.
4. The operating shaft as claimed in
the tubular semi-finished product for the shaft tube includes steel and is at least externally electrochemically galvanized in conjunction with die-cast zinc being used as the material for the levers.
5. The operating shaft as claimed in
wherein each lever is formed as a unit with concentric projections adjacent thereto on both sides, formed by a separate die-cast body.
7. A method of claim for producing an operating shaft, comprising:
provisioning a split casting mold for a lever, positioning a shaft tube in the split casting mold with a sealed closure on the circumference for the shaft tube, introducing a molten liquid die-casting material into the split casting mold in order to form at least one lever, which are concentric with respect to the shaft tube.
8. The method of
introducing a molten liquid die-casting material into the split casting mold in order to form at least one lever, which is concentric with respect to the shaft tube.
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This application is the national phase application under 35 U.S.C. § 371 of PCT International Application No. PCT/DE99/03770 which has an International filing date of Nov. 24, 1999, which designated the United States of America.
The invention relates to an operating shaft for operation of switching contacts in a multipole electrical power circuit breaker having levers, which project from a central shaft tube (which is intended to provide a rotating bearing) and which are composed of die-cast metal, for connecting the operating shaft to the switching contacts and to an energy store which operates the switching contacts. The invention also relates to a method for producing such an operating shaft.
An operating shaft has been disclosed in DE 197 27 853 C1. In order to simplify the production of relatively long operating shafts, such as those which are required for four-pole power circuit breakers and those with a high rated current, the cited document provides for relatively short operating shaft units to be coupled to one another. In contrast, it would appear to be advantageous if it were possible to provide integral operating shafts with identical characteristics for all sizes in a range of power circuit breakers, and which are produced using the same method. The invention is based on the object of providing an operating shaft having these characteristics.
According to the invention, the above object is achieved in that the shaft tube is formed by a section of a tubular semi-finished product which is composed of a metal which has a higher melting point than that of the levers which project from the shaft tube, and in that the levers are mounted on the shaft tube.
The invention combines with one another the advantages of operating shafts which are produced from prefabricated individual parts by soldering or welding, and those which are produced as die-cast parts in accordance with the cited DE 197 27 853 C1. The fitting of the levers to a shaft tube comprising a tubular semi-finished product allows operating shafts to be produced cost-effectively of any required length and with any required number of levers. The advantageous characteristics of the new operating shaft are thus related to the production of die-cast parts of smaller size than is the case according to the cited DE 197 27 853 C1. Among other factors, this considerably reduces the quality assurance effort.
Relatively short operating shafts, such as those which are required for power circuit breakers having a normal number of poles and with a low to medium rated current can be constructed, according to one refinement of the invention, in such a manner that all the levers are formed by an integral die-cast body, with sections of the die-cast body which enclose the shaft tube in the form of a casing being arranged between the levers. However, to produce long operating shafts, it may be better to form each lever as a unit with concentric projections adjacent to it on both sides. This allows there to be exposed sections of the tubular semi-finished product between the levers.
Should it be found that the fitting of a die-cast material to the tubular semi-finished product does not at the same time achieve a strength which is sufficient for transmitting the required forces, then suitable roughening, profiling or the arrangement of depressions in the semi-finished product can be used to improve the force fit. A good connection can in consequence be achieved with particularly low effort in that the tubular semi-finished product for the shaft tube is composed of steel and is at least externally electrochemically galvanized in conjunction with die-shaft zinc being used as the material for the levers.
An expedient method for producing operating shafts with the characteristics described above comprises the following steps:
provision of a shaft tube composed of a tubular semi-finished product,
provision of a split casting mold for at least one of the levers and concentric projections which extend in the axial direction of the semi-finished product on both sides of the lever,
positioning of the shaft tube in the casting mold with a sealed closure on the circumference of the shaft tube,
introduction of a molten liquid die-casting material into the casting mold in order to form the lever and the adjacent projections, which are concentric with respect to the shaft tube,
opening of the casting mold once the die-casting material has cooled down to a reasonable extent, and removal of the shaft tube with die-cast bodies, which are attached thereto and have at least one lever and adjacent sections in the form of casings.
The invention will be explained in more detail in the following text with reference to the exemplary embodiments, which are illustrated in the figures, in which:
In an illustration corresponding to that in
The method procedure for producing an operating shaft according to the invention is illustrated in FIG. 4.
The operating shaft 1 as shown in
The operating shaft 10, a further example of which is shown in
The fundamental method procedure for producing the operating shafts 1 or 10 will be explained in the following text with reference to FIG. 4. In this case, in order to simplify the description, it is assumed that an operating shaft 10 as shown in
The method as shown in
The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.
Godesa, Ludvik, Petznik, Peter
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Executed on | Assignor | Assignee | Conveyance | Frame | Reel | Doc |
Apr 02 2001 | GODESA, LUDVIK | Siemens Aktiengesellschaft | ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS | 012045 | /0918 | |
Apr 02 2001 | PETZNIK, PETER | Siemens Aktiengesellschaft | ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS | 012045 | /0918 | |
Aug 17 2001 | Siemens Aktiengesellschaft | (assignment on the face of the patent) | / |
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